Sea level rise is a major consequence and indicator of climate change. The global mean sea level rise is mainly induced by thermal expansion and land ice melt. Sea level rise is highly non-uniform. Various mechanisms can cause spatial variability of sea level rise including ocean dynamics, the geoid change induced by land ice melt, and vertical land motion. Dynamic sea level is the sea level deviation from the geoid. It is closely related to ocean current through geostrophy. In the current climate, dynamic sea level shows complex patterns. It is very low in the North Atlantic compared to the North Pacific. In addition, there are sharp gradients across the narrow and strong western boundary currents such as the Gulf Stream and Kuroshio. The peak-to-peak dynamic sea level difference can be up to 3 m.

Satellite observed mean dynamic sea level

The projections from the GFDL CM2.1 climate model indicate that the northeast coast of the US will experience a rapid sea level rise over the 21st century. In response to a mid-range increase in greenhouse-gas concentrations (SRES A1B scenario), the dynamic sea level rise reaches 20 cm at New York City by the end of this century. It is caused by a slowdown of the Atlantic overturning circulation. The dynamic sea level rise will be superimposed on the global mean sea level rise, leading to high vulnerability of the northeastern US coast.